A belt formed by juxtaposing a plurality of metal pieces called an “element” or a “block” in a circular manner, and by fastening the juxtaposing metal pieces by an endless carrier (called a “ring” or a “hoop”) is known in the prior art to be used in a continuously variable transmission. The belt of this kind is adapted to transmit the torque by a pushing force among the metal pieces thus juxtaposed to be contacted to one another. Specifically, the metal pieces existing in the groove of a drive pulley are sequentially pushed out of the groove by a rotation of the pulley while pushing the metal pieces in front of those metal pieces. The metal pieces thus being pushed forward are eventually entered into a groove of a driven pulley. As a result, the torque of the drive pulley is transmitted to the driven pulley by such advancement of the metal pieces.
An example of the belt thus structured is disclosed in Japanese Patent Laid-Open No. 2000-205342. According to the teachings of Japanese Patent Laid-Open No. 2000-205342, an annular belt is formed by fastening a plurality of trapezoidal blocks using two rows of endless carriers. A block 100 is shown in FIG. 8 of the present application in more detail. The blocks 100 shown in FIG. 8 are juxtaposed annularly in an orientation to situate a short side thereof in an inner circumferential side. Lateral faces 101 and 102 of the block 100 thus juxtaposed are respectively inclined to be parallel to inner faces of a V-shaped groove of a not shown pulley. In the width center at the center of height of the block 100, there is formed a saddle face 104 on which the endless carriers 103 are disposed. A width of the saddle face 104 is wider than the total width of the carried 103 arranged parallel to each other.
In addition, in order to prevent a detachment of the endless carrier 103 from the saddle face 104, in other words, in order to prevent a disengagement of the block 100 from the endless carrier 103, the block 100 comprises stopper portions 105 and 106. Specifically, a shape of the stopper portions 105 and 106 is inverse L-shaped portion, and those the stopper portions 105 and 106 are erected respectively on both width ends of the saddle face 104 to cover width end portions of the endless carriers 103 from above. A clearance between the stopper portions 105 and 106 serves as an opening 107 to the saddle face 104. Protruding portions 108 and 109 whose cross-section is arcuate are respectively formed on one of the faces (e.g., on the front face) of the stopper portions 105 and 106, and (not shown) concave portions are respectively formed on the opposite side of the protruding portions 108 and 109. Therefore, the protruding portions 108 and 109 are respectively inserted into the concave portions of the adjoining block 100.
The belt for continuously variable transmission thus has been explained is adapted to transmit the torque by the pushing force among the blocks. For this purpose, the blocks 100 are juxtaposed tightly to one another in order not to create clearances thereamong, and fastened by the endless carriers. According to the belt taught by Japanese Patent Laid-Open No. 2000-205342, the endless carriers are situated in the width center of the block. Therefore, the blocks being juxtaposed tightly in a circular manner cannot be fastened by the carrier entirely at the same time. For this reason, the blocks have to be fastened by the endless carrier one by one, or several pieces at a time.
However, as previously mentioned, the blocks are juxtaposed by inserting the protruding portion loosely into the concave portion of the adjoining block. Therefore, in case of inserting the last piece of the blocks to be fastened into an array of the blocks already been fastened by the endless carrier, only a clearance comparable with a thickness of the last piece of the blocks to be fastened is available in the array of the blocks. For this reason, the protruding portion of the last piece of the blocks to be fastened may be contacted with the blocks already been fastened by the endless carrier, and this makes the assembling work difficult at the final phase. Especially, since a circumferential length of the belt assembled in a circular manner is relatively shorter in its inner circumferential side, the clearances among the juxtaposed elements are narrowed in the inner circumferential side of the belt. Therefore, in case the protruding portions and the concave portions are formed on the block in the inner circumferential side of the annular belt, the assembling work of the belt has to be much more difficult.